A copper complex constructed by the ligand( L): 1,1-dimethyl-1-ethylene-2,2-dimercapto has been synthesized and its structure has been determined by means of X-ray single crystal diffraction. The central copper(II) ion coordinates with two L which constructed a square environment. Intermolecular C-H center dot center dot center dot S hydrogen bonds and pi-pi stacking interactions among ligand groups leading to the formation of a multi-dimensional supramolecular network. Its third-order nonlinear optical property has been studied using Z-scan technique with 20 picosecond (ps) pulses at wavelength 532 nm. Its molecular second hyperpolarizability gamma achieved 10(31) esu. (C) 2009 Elsevier B. V. All rights reserved.